Useful next calculations
Rates and sources
UK energy unit rates vary by region and supplier. Ofgem publishes a price cap refreshed each quarter.
Source: Ofgem — Energy price cap. Check the linked guidance and any live quote before acting.
When to use this calculator
- Before switching supplier, upgrading equipment or comparing energy-saving changes.
- When you want to test different usage or price scenarios quickly.
- When you need a simple estimate before requesting installer or supplier quotes.
- When a tariff is about to change and you want to model the bill impact.
A worked example
These are the example figures the calculator opens with.
| Input | Value |
|---|---|
| Usage Per Day (kWh) | 8 |
| Price Per kWh (£) | £0.24 |
For those figures the calculator returns:
- Daily: £1.92
- Monthly: £58.37
- Annual: £700.80
Method & assumptions
This calculator multiplies the daily kilowatt-hour use you enter by the unit rate you enter. It does not add a standing charge, capacity charge or tax. If your bill quotes a tax-inclusive unit rate, enter that figure to estimate daily, monthly and annual energy cost. Usage is treated as constant across the year, which is a planning simplification.
Common mistakes
- Using the current tariff without testing a higher unit rate.
- Forgetting the standing charge when comparing annual bills.
- Treating the result as a supplier quote.
- Using optimistic savings figures for an upgrade without a written estimate.
What to do next
- Run the same scenario with a 10% higher unit rate.
- Compare this result with a related energy calculator before requesting installer quotes.
- If you are evaluating an upgrade, rerun with actual quote figures.
- Set a reminder to rerun the calculation when your tariff renews.
Questions people ask
Daily cost is kWh per day multiplied by the unit rate you enter. Monthly and annual figures scale that daily cost. Standing charges and tax are not added, so use the unit rate as it appears on your bill if you want an all-in energy unit cost.